Electrical stimulator

Abstract

To provide an electrical stimulation device that enables the application of diverse electrical stimuli. [Solution] The electrical stimulation device 1 comprises a DC power supply unit 20 and an electrical stimulation unit 10 to which power is supplied from the DC power supply unit 20. The electrical stimulation unit 10 includes a first switching element Q1 and a second switching element Q2 connected in series between the high-side reference line and the low-side reference line of the DC power supply unit 20, a first electrode unit P1 connected between the first switching element Q1 and the second switching element Q2 to be in contact with a part of the human body Hd, a third switching element Q3 and a fourth switching element Q4 connected in series between the high-side reference line and the low-side reference line, and a second electrode unit P2 connected between the third switching element Q3 and the fourth switching element Q4 to be in contact with another part of the human body Hd. The electrical stimulation device 1 includes a current control unit capable of controlling the current flowing from the electrical stimulation unit 10 to the low-side reference line.

Description

[Technical Field]

[0001] The present invention relates to an electrical stimulation device. [Background Art]

[0002] Electrical stimulation devices that apply electrical stimulation to a user's muscles are known. An electrical stimulation device can pass a weak current through muscles to tense and relax the muscles, thereby passively moving the muscles.

[0003] Patent Document 1 discloses a low-frequency therapy apparatus provided with a pair of positive and negative output electrodes. Patent Document 1 also discloses a technology in which a battery voltage is boosted to generate a boost pulse, a high voltage is temporarily accumulated in a capacitor serving as a power source for a stimulation pulse current, a voltage value is variably set, the set set voltage value is compared with a charging voltage value of the capacitor, and a boost pulse to the capacitor is stopped when the charging voltage value exceeds the set voltage value. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Examined Patent Publication No. 6-57263 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] According to the low-frequency therapy apparatus disclosed in Patent Document 1, the output voltage to the human body can be changed by changing the charging voltage value of the capacitor, so that the intensity of stimulation can be changed. However, in the technology disclosed in Patent Document 1, it is necessary to use comparison with a set voltage value to change the charging voltage value of the capacitor, which makes it difficult to adjust the output voltage and also causes a problem in responsiveness. Therefore, it has been difficult to apply various types of electrical stimulation to a user's muscles.

[0006] The present invention was made in these circumstances, and one exemplary objective of a certain embodiment is to provide an electrical stimulation device that enables the application of a variety of electrical stimuli. [Means for solving the problem]

[0007] To solve the above problems, an electrical stimulation device according to one aspect of the present invention comprises a DC power supply unit and an electrical stimulation unit to which power is supplied from the DC power supply unit, wherein the electrical stimulation unit includes a first switching element and a second switching element connected in series between the high-side reference line and the low-side reference line of the DC power supply unit, a first electrode unit connected to a first connection point between the first switching element and the second switching element to be in contact with a part of the human body, a third switching element and a fourth switching element connected in series between the high-side reference line and the low-side reference line, and a second electrode unit connected to a second connection point between the third switching element and the fourth switching element to be in contact with another part of the human body, and further comprises a current control unit capable of controlling the current flowing from the electrical stimulation unit to the low-side reference line.

[0008] Furthermore, any combination of the above components, or any substitution of the components or expressions of the present invention between methods, apparatus, systems, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0009] According to the present invention, an electrical stimulation device that enables the application of diverse electrical stimuli can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the circuit configuration of an electrical stimulation device according to the first embodiment. [Figure 2] This diagram illustrates the AC voltage waveform applied between a pair of electrodes. [Figure 3] This figure illustrates an example of an AC voltage waveform applied between a pair of electrodes during one cycle. [Figure 4] This is a time chart showing an example of how pulse current changes when the reference voltage is varied with each period. [Figure 5] This is a time chart showing another example of how pulse current changes when the reference voltage is varied with each period. [Figure 6] This figure shows an example of the circuit configuration of an electrical stimulation device according to the second embodiment. [Figure 7] This figure shows an example of the circuit configuration of the integrated control unit shown in Figure 6. [Figure 8] This figure shows a truth table that defines the relationship between the logic of the SEL_A signal line and the SEL_B signal line and the switching elements that are turned on. [Modes for carrying out the invention]

[0011] The present invention will be described below with reference to the drawings, based on preferred embodiments. The embodiments are illustrative and not limiting, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. In the embodiments and modifications, the same or equivalent components and members will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0012] (First Embodiment) Figure 1 shows an example of the circuit configuration of an electrical stimulator 1 according to the first embodiment. The electrical stimulator 1 is an EMS (Electrical Muscle Stimulation) device that provides electrical stimulation to the user's muscles. The electrical stimulator 1 is a portable EMS device that is powered, for example, by a battery. The electrical stimulator 1 comprises an electrical stimulation unit 10, a DC power supply unit 20, a control unit 30, and a constant current circuit 50. The electrical stimulation unit 10 includes a first switching element Q1 to a fourth switching element Q4 connected in an H-bridge, a pair of first electrode units P1 and second electrode units P2. The DC power supply unit 20 includes a boost circuit and outputs a boosted voltage VB. The electrical stimulation unit 10 is supplied with power from the DC power supply unit 20 at the boosted voltage VB. The constant current circuit 50 includes a first operational amplifier OP1, a second operational amplifier OP2, and a shunt resistor RSH Includes.

[0013] The electrical stimulation device 1 is used with a pair of first electrode parts P1 and second electrode parts P2 in contact with any part of the human body Hd. By contacting one part of the human body Hd with the first electrode part P1 and another part of the human body Hd with the second electrode part P2, an electrical current path is formed with the human body Hd as the load.

[0014] The pair of first electrode sections P1 and second electrode sections P2 are electrodes that do not require consumable gel pads, and are specifically cloth electrodes. Cloth electrodes are used after being moistened with water. Cloth electrodes have a long lifespan, meaning they can be used many times before reaching the end of their lifespan. Cloth electrodes are also washable. The pair of first electrode sections P1 and second electrode sections P2 may be electrodes other than cloth electrodes, such as metal. The pair of first electrode sections P1 and second electrode sections P2 may also be electrodes that require gel pads. The pair of first electrode sections P1 and second electrode sections P2 may also be rubber electrodes such as EPDM (Ethylene Propylene Diene Monomer) rubber or conductive polyurethane. Rubber electrodes can be used without moistening with water.

[0015] A first arm and a second arm are connected in parallel between the high-side reference line and the low-side reference line of the DC power supply unit 20. The first arm includes a first switching element Q1 and a second switching element Q2 connected in series, and a first connection point N1 between the first switching element Q1 and the second switching element Q2 is connected to the first electrode unit P1. The second arm includes a third switching element Q3 and a fourth switching element Q4 connected in series, and a second connection point N2 between the third switching element Q3 and the fourth switching element Q4 is connected to the second electrode unit P2.

[0016] Semiconductor switching elements such as bipolar transistors, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and IGBTs (Insulated Gate Bipolar Transistors) can be used for the first switching element Q1 to the fourth switching element Q4. However, as will be described later, it is preferable that the second switching element Q2 and the fourth switching element Q4 are MOSFETs. Below, we will assume an example in which P-type MOSFETs are used for the first switching element Q1 and the third switching element Q3, and N-type MOSFETs are used for the second switching element Q2 and the fourth switching element Q4.

[0017] In this case, the source terminal of the first switching element Q1 is connected to the high-side reference line, the source terminal of the second switching element Q2 is connected to the low-side reference line, and the connection point between the drain terminal of the first switching element Q1 and the drain terminal of the second switching element Q2 becomes the first connection point N1. Similarly, the source terminal of the third switching element Q3 is connected to the high-side reference line, the source terminal of the fourth switching element Q4 is connected to the low-side reference line, and the connection point between the drain terminal of the third switching element Q3 and the drain terminal of the fourth switching element Q4 becomes the second connection point N2.

[0018] The control unit 30 controls the entire electrical stimulation device 1. The control unit 30 can be composed of one or any combination of a microcontroller, FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), gate IC, or other LSI.

[0019] The control unit 30 outputs control signals for the first switching element Q1 to the fourth switching element Q4. The control signal for the first switching element Q1 output from the control unit 30 is input to the first drive circuit Dr1. Based on the control signal for the first switching element Q1 input from the control unit 30, the first drive circuit Dr1 generates a drive signal for the first switching element Q1 and drives the first switching element Q1. Similarly, the control signal for the third switching element Q3 output from the control unit 30 is input to the third drive circuit Dr3. Based on the control signal for the third switching element Q3 input from the control unit 30, the third drive circuit Dr3 generates a drive signal for the third switching element Q3 and drives the third switching element Q3.

[0020] The control signal for the fourth switching element Q4 output from the control unit 30 is input to the non-inverting input terminal of the first operational amplifier OP1 included in the constant current circuit 50. The main functions of the first operational amplifier OP1 will be described later, but the first operational amplifier OP1 also functions as a fourth drive circuit that drives the fourth switching element Q4 by generating a drive signal for the fourth switching element Q4 based on the control signal for the fourth switching element Q4 input from the control unit 30. Alternatively, a fourth drive circuit may be separately placed between the output terminal of the first operational amplifier OP1 and the gate terminal of the fourth switching element Q4. Similarly, the control signal for the second switching element Q2 output from the control unit 30 is input to the non-inverting input terminal of the second operational amplifier OP2 included in the constant current circuit 50. The main functions of the second operational amplifier OP2 will be described later, but the second operational amplifier OP2 also functions as a second drive circuit that drives the second switching element Q2 by generating a drive signal for the second switching element Q2 based on the control signal for the second switching element Q2 input from the control unit 30. Furthermore, a second drive circuit may be separately placed between the output terminal of the second operational amplifier OP2 and the gate terminal of the second switching element Q2. Hereinafter, the first drive circuit Dr1, the second drive circuit as a function of the second operational amplifier OP2, the third drive circuit Dr3, and the fourth drive circuit as a function of the first operational amplifier OP1 will be collectively referred to simply as the drive circuit.

[0021] In this embodiment, since MOSFETs are used for the first switching element Q1 to the fourth switching element Q4, each drive circuit is a circuit that generates a gate voltage supplied to the gate terminals of the first switching element Q1 to the fourth switching element Q4, respectively. If bipolar transistors are used for the first switching element Q1 to the fourth switching element Q4, each drive circuit is a circuit that generates a base current supplied to the base terminals of the first switching element Q1 to the fourth switching element Q4, respectively. If the control unit 30 includes a gate IC and has sufficient driving capability, each drive circuit can be composed only of passive elements such as resistors. Hereinafter, terminals used to switch the switching elements on and off, such as the gate terminals of MOSFETs and the base terminals of bipolar transistors, will be collectively referred to as control terminals.

[0022] The control unit 30 can apply a positive voltage between the first electrode section P1 and the second electrode section P2 by controlling the first switching element Q1 and the fourth switching element Q4 to the ON state and the second switching element Q2 and the third switching element Q3 to the OFF state. The control unit 30 can apply a negative voltage between the first electrode section P1 and the second electrode section P2 by controlling the first switching element Q1 and the fourth switching element Q4 to the OFF state and the second switching element Q2 and the third switching element Q3 to the ON state.

[0023] In this embodiment, the control unit 30 controls the electrical stimulation unit 10 as follows: In one cycle, the control unit 30 alternately applies a positive pulse voltage and a negative pulse voltage multiple times between the first electrode unit P1 and the second electrode unit P2, and then inserts an interval period. More specifically, in one cycle, the control unit 30 alternately applies a positive pulse voltage and a negative pulse voltage an odd number of times between the first electrode unit P1 and the second electrode unit P2, and then inserts an interval period. In the next cycle, the control unit 30 applies an odd number of pulse voltages with the phases of the odd number of pulse voltages inverted, and then inserts an interval period.

[0024] Figure 2 is a diagram illustrating the AC voltage waveform applied between a pair of first electrode sections P1 and second electrode sections P2. The voltage waveform shown in Figure 2 is composed of a combination of positive and negative fundamental pulses with a time width t1. The positive fundamental pulse causes a positive current to flow from one of the pair of first electrode sections P1 and second electrode sections P2 to the other, and the negative fundamental pulse causes a negative current to flow from the other to the first.

[0025] A pause period of time width t2 is provided between positive and negative fundamental pulses. The applied voltage during this pause period is 0. In this waveform, a group of fundamental pulses with a time width t3 (= 5 × t1 + 5 × t2) is formed, consisting of 5 fundamental pulses and 5 pause periods. This group of fundamental pulses, together with the subsequent interval period of time width t4, forms a fundamental waveform with one period (time width) t5 (= t3 + t4).

[0026] For example, if the time interval t1 is set to 100us and the time interval t2 is set to 100us, the time interval t3 will be 1ms. In this embodiment, the user can select between Mode A (20Hz mode) and Mode B (4Hz mode). When Mode A is selected, the time interval t5 will be 50ms (=20Hz) and the time interval t4 (interval period) will be 49ms. When Mode B is selected, the time interval t5 will be 250ms (=4Hz) and the time interval t4 (interval period) will be 249ms.

[0027] In the example shown in Figure 2, the voltage polarity of the basic pulse is reversed for each waveform group. That is, if in a given waveform group a positive pulse voltage is output 3 times and a negative pulse voltage is output 2 times, then in the next waveform group, the number of times a positive pulse voltage is output 2 times and the number of times a negative pulse voltage is output 3 times will be repeated alternately. This allows for the suppression of charge imbalance on the first electrode part P1 and the second electrode part P2 by treating the two waveform groups as a pair, thereby suppressing corrosion of the first electrode part P1 and the second electrode part P2. Note that the pulse voltage application pattern shown in Figure 2 is just one example and is not limited to this application pattern. For example, a pattern in which positive and negative pulse voltages are not applied alternately but each is applied multiple times consecutively may be used. Alternatively, a pattern in which the pulse voltage is applied an even number of times in one cycle may be used. Furthermore, a pattern in which multiple pulse voltages with different time widths are applied in one cycle may be used. Furthermore, a pattern may be used in which at least one positive pulse voltage and at least one negative pulse voltage are applied at least once during a single cycle.

[0028] Figure 3 illustrates an example of an AC voltage waveform applied between a pair of first electrode sections P1 and second electrode sections P2 in one cycle. In Figure 3, (a) shows an example similar to the voltage waveform shown in Figure 2. (b) shows an example of an AC voltage waveform when a pattern is used in which only a positive pulse voltage is applied once in one cycle. (c) shows an example of an AC voltage waveform when a pattern is used in which a positive pulse voltage is applied twice and a negative pulse voltage is applied once in one cycle. In (c), the time width of the second positive pulse voltage and the time width of the negative pulse voltage are greater than the time width of the first positive pulse voltage.

[0029] Before explaining the constant current circuit 50, let's briefly explain the background for using the constant current circuit 50 in the electrical stimulator 1. Even if the electrical stimulator 1 is not equipped with the constant current circuit 50, as described above, it is possible to apply a pulse voltage between a pair of first electrode parts P1 and second electrode parts P2 that are made to contact any part of the human body Hd. This allows the muscles of the human body Hd to be passively moved by passing a weak electric current through them, causing them to tense and relax.

[0030] However, electrical stimulators that do not have a constant current circuit 50 have room for improvement in terms of providing diverse stimuli to the muscles of the human body Hd. For example, in order to provide a relaxing effect to the muscles of the human body Hd, it is considered effective to change the intensity of the pulse voltage periodically. One possible method for changing the intensity of the pulse voltage periodically is to change the output voltage from the DC power supply unit 20 over time. However, even if one attempts to change the output voltage from the DC power supply unit 20 over time, voltage drops are likely to occur due to charge consumption by the load, making it difficult to generate the desired waveform. Furthermore, even if it were possible to change the intensity of the pulse voltage over time, it would be difficult to change the intensity of the pulse voltage at a frequency sufficient to provide a relaxing effect to the muscles of the human body Hd, for example, at several tens of Hz. This is particularly problematic when the power from the DC power supply unit 20 is relatively small, such as when the electrical stimulator 1 is a portable electrical stimulator.

[0031] Therefore, the electrical stimulator 1, equipped with a constant current circuit 50, can provide diverse stimuli to the muscles of the human body Hd. The details of the constant current circuit 50 will be described below.

[0032] Returning to Figure 1, the constant current circuit 50 consists of the first operational amplifier OP1, the second operational amplifier OP2, and the shunt resistor R. SH Includes shunt resistor R SH This is connected between the electrical stimulation unit 10 and the low-side reference line of the DC power supply unit 20. When the second switching element Q2 and the fourth switching element Q4 are N-type MOSFETs as described above, the shunt resistor R SHThe position connected to the electrical stimulation unit 10 is between the source terminal of the second switching element Q2 and the source terminal of the fourth switching element Q4.

[0033] The inverting input terminal of the first operational amplifier OP1 is connected to the shunt resistor R between the electrical stimulation unit 10 and the shunt resistor R SH to the third connection point N3 between them. The output terminal of the first operational amplifier OP1 is connected to the control terminal of the fourth switching element Q4. To the non-inverting input terminal of the first operational amplifier OP1, the reference voltage V is supplied from the control unit 30 REF 1 is applied. With this configuration, the first operational amplifier OP1 performs a negative feedback operation such that the potential of the inverting input terminal matches the reference voltage V applied to the non-inverting input terminal REF 1, and controls the fourth switching element Q4 accordingly. That is, between the electrical stimulation unit 10 and the shunt resistor R SH the voltage therebetween is V REF 1 is maintained. At this time, the shunt resistor R SH the current I1 flowing through it is, according to Ohm's law, I1=V REF 1 / R SH holds. For example, V REF 1=0.8V, R SH =10Ω, then I1=80mA. Further, since this current I1 is forcibly controlled by the high gain of the first operational amplifier OP1, it is maintained constant regardless of the load such as muscles of the human body Hd between the pair of the first electrode unit P1 and the second electrode unit P2. Then, the control unit 30 adjusts the reference voltage V REF 1 is changed for each cycle, whereby the pulse current I flowing through a load such as a muscle of the human body Hd EMS (see FIG. 4, etc.) can be controlled such that its intensity changes over a plurality of cycles.

[0034] The inverting input terminal of the second operational amplifier OP2 is connected to the shunt resistor R between the electrical stimulation unit 10 and the shunt resistor R SH to the third connection point N3 between them. The output terminal of the second operational amplifier OP2 is connected to the control terminal of the second switching element Q2. To the non-inverting input terminal of the second operational amplifier OP2, the reference voltage V is supplied from the control unit 30 REFA voltage of 2 is applied. In this configuration, the second operational amplifier OP2 performs negative feedback operation, similar to the first operational amplifier OP1, and the potential of the inverting input terminal is equal to the reference voltage V applied to the non-inverting input terminal. REF The second switching element Q2 is controlled so that it becomes equal to 2. At this time, the shunt resistor R SH The current I2 flowing through it is, like the current I1 mentioned above, given by Ohm's law, I2 = V REF 2 / R SH This is how it works. The constant current circuit 50 and the control unit 30 constitute a current control unit capable of controlling the current flowing from the electrical stimulation unit 10 to the low-side reference line of the DC power supply unit 20. In this way, the electrical stimulation device 1 can supply a constant current between the pair of first electrode units P1 and second electrode units P2 without being affected by the load, thanks to the constant current circuit 50. The control unit 30 then controls the reference voltage V REF By changing 2 periodically, pulse current I flows through the load on the muscles, etc., of the human body Hd. EMS The intensity can be controlled to change over multiple periods.

[0035] Here, we will explain why it is preferable to use MOSFETs for the second switching element Q2 and the fourth switching element Q4. In the constant current circuit 50, the shunt resistor R SH It is necessary to precisely control the current flowing through it. However, when a bipolar transistor is used for the second switching element Q2 or the fourth switching element Q4, since the bipolar transistor is a current-driven element, the base current from the base terminal, which acts as the control terminal, is separate from the collector current and is controlled by the shunt resistor R SH This causes the pulse current I to flow through the load on the muscles, etc. of the human body Hd. EMS and shunt resistor R SH Because the current flowing through it is different from that of the constant current circuit 50, the accuracy of the constant current circuit 50 may decrease. On the other hand, when a MOSFET is used for the second switching element Q2 or the fourth switching element Q4, since the MOSFET is a voltage-driven element, the shunt resistor R from the gate terminal SHThe current flowing through it is much smaller than that of a bipolar transistor. Therefore, using a MOSFET for the second switching element Q2 or the fourth switching element Q4 can improve the accuracy of the constant current circuit 50.

[0036] Figure 4 shows the reference voltage V REF 1. V REF The pulse current I when 2 is changed at each periodic interval. EMS This is a time chart showing an example of the changes. Figure 4 shows the boosted voltage VB from the DC power supply unit 20 and the reference voltage V REF 1. Reference voltage V REF 2. Pulse current I EMS These are shown respectively. Figure 4 shows a pattern in which a positive pulse voltage is applied once and a negative pulse voltage is applied once in one cycle. Specifically, when the control unit 30 applies a positive pulse voltage once, it controls the first switching element Q1 and the fourth switching element Q4 to the ON state and the second switching element Q2 and the third switching element Q3 to the OFF state, thereby applying a reference voltage V to the non-inverting input terminal of the first operational amplifier OP1. REF A pulse voltage of 1 is applied. Similarly, when the control unit 30 applies a negative pulse voltage once, it controls the second switching element Q2 and the third switching element Q3 to the ON state and the first switching element Q1 and the fourth switching element Q4 to the OFF state, thereby setting a reference voltage V to the non-inverting input terminal of the second operational amplifier OP2. REF A pulse voltage of 2 is applied. In this way, the control unit 30 applies a reference voltage V to the non-inverting input terminals of the first operational amplifier OP1 and the second operational amplifier OP2. REF 1. V REF By controlling 2, the pulse current I EMS It is controllable.

[0037] As shown in Figure 4, pulse current I EMS Each time the current flows, the boosted voltage VB decreases. This is thought to be due to the voltage drop caused by charge consumption by the load. Even in such a case, if the decrease in the boosted voltage VB is within an appropriate range, the pulse current I EMSIt can be controlled without being affected by the decrease in the boost voltage VB. Conversely, if the decrease in the boost voltage VB exceeds the appropriate range, the achievable pulse current I EMS The upper limit of the intensity is limited, and the pulse current I that the control unit 30 tries to control is limited. EMS The required intensity cannot be obtained. In other words, it is preferable that the decrease in the boosted voltage VB is within an appropriate range. Furthermore, the control unit 30 controls the reference voltage V REF 1. V REF By changing 2 periodically, the pulse current I EMS The intensity can be controlled to change over multiple periods. In Figure 4, the control unit 30 controls the reference voltage V REF 1. V REF By gradually increasing 2 with each period, the pulse current I EMS This shows a process in which the intensity gradually increases over multiple periods.

[0038] Figure 5 shows the reference voltage V REF 1. V REF The pulse current I when 2 is changed at each periodic interval. EMS Figure 5 is a time chart showing another example of the change. Similar to Figure 4, Figure 5 shows the boosted voltage VB from the DC power supply 20 and the reference voltage V REF 1. Reference voltage V REF 2. Pulse current I EMS These are shown respectively. In Figure 5, the pulse current I over a longer period than in Figure 4 is shown. EMS This shows the change. Also, Figure 5 shows a simplified waveform of the pulse voltage in one period.

[0039] As shown by the dashed line in Figure 5, the control unit 30 controls the pulse current I EMS The intensity of the pulse current I can be controlled to change sinusoidally over multiple periods. This sine wave is, for example, approximately 10 Hz. EMS By changing the intensity of the signal in a sinusoidal wave pattern of approximately 10 Hz, it is possible to provide a relaxing effect to the muscles of the human body Hd, especially the deep muscles such as the psoas muscle. Note that in Figure 5, the boosted voltage VB also appears to be changing in a sinusoidal wave pattern, which is due to the effect of the voltage drop explained in Figure 4.

[0040] The control unit 30 is not limited to the sinusoidal waveform shown in Figure 5, but also to pulse current I EMS The intensity can be controlled to change to any shape over multiple cycles. This allows for diverse stimuli to be applied to the muscles of the human body Hd. The control unit 30 controls the pulse current I EMS The shape that changes the intensity over multiple periods may be, for example, a triangular wave, a sawtooth wave, or any combination of these shapes including a sinusoidal wave.

[0041] The electrical stimulation device 1 may have two additional coupling capacitors as a modification of the circuit configuration example shown in Figure 1. For example, in Figure 1, a first coupling capacitor (not shown) is inserted between the first connection point N1 of the H-bridge circuit and the first electrode part P1, providing DC isolation between the first connection point N1 and the first electrode part P1. A second coupling capacitor (not shown) is inserted between the second connection point N2 of the H-bridge circuit and the second electrode part P2, providing DC isolation between the second connection point N2 and the second electrode part P2.

[0042] By adding a first coupling capacitor in series between the H-bridge circuit and the first electrode section P1, and a second coupling capacitor in series between the H-bridge circuit and the second electrode section P2, the DC current flowing from the electrical stimulator 1 to the human body Hd can be cut off. As described above, the pulse current I supplied from the electrical stimulator 1 to the human body Hd EMS Since it is an AC pulse, it passes through the first and second coupling capacitors and does not affect steady-state operation.

[0043] (Second Embodiment) Figure 6 shows an example of the circuit configuration of the electrical stimulation device 3 according to the second embodiment. The electrical stimulation device 3 is an EMS device that provides electrical stimulation to the user's muscles. The electrical stimulation device 3 is a portable EMS device that is powered, for example, by a battery. The electrical stimulation device 3 comprises a plurality of electrical stimulation units 10, a DC power supply unit 20, and an integrated control unit 80. The DC power supply unit 20 is the same as the DC power supply unit 20 provided in the electrical stimulation device 1 according to the first embodiment. Although not shown in Figure 6, a shunt resistor is connected between each of the plurality of electrical stimulation units 10 and the low-side reference line of the DC power supply unit 20.

[0044] Multiple electrical stimulation units 10 may be built into a single piece of fitness wear. Below, we assume an example in which four electrical stimulation units 10a-10d are provided as multiple electrical stimulation units 10. For example, the first electrode P1a and the second electrode P2a of the first electrical stimulation unit 10a are attached to the right arm, and the first electrical stimulation unit 10a can provide electrical stimulation to the biceps brachii and triceps brachii muscles. The first electrode P1b and the second electrode P2b of the second electrical stimulation unit 10b are attached to the abdomen (one of which may be attached to the waist), and the second electrical stimulation unit 10b can provide electrical stimulation to the rectus abdominis and oblique abdominal muscles.

[0045] The first electrode P1c and second electrode P2c of the third electrical stimulation unit 10c are attached to the right foot (one may be attached to the buttocks), and the third electrical stimulation unit 10c can deliver electrical stimulation to the quadriceps femoris and buttocks of the right foot. The first electrode P1d and second electrode P2d of the fourth electrical stimulation unit 10d are attached to the left foot (one may be attached to the buttocks), and the fourth electrical stimulation unit 10d can deliver electrical stimulation to the quadriceps femoris and buttocks of the left foot.

[0046] Figure 7 shows an example of the circuit configuration of the integrated control unit 80. The integrated control unit 80 includes a control unit 30A, an operational amplifier OP, and a multiplexer 32.

[0047] The control unit 30A and the multiplexer 32 are connected by four signal lines (EMS_H signal line, EMS_L signal line, SEL_A signal line, and SEL_B signal line). The EMS_H signal line is a signal line for turning on the high-side switching element of the H-bridge circuit, and the EMS_L signal line is a signal line for turning on the low-side switching element of the H-bridge circuit. The SEL_A signal line and SEL_B signal line are signal lines for transmitting 2-bit control signals.

[0048] Here, the EMS_L signal line includes an operational amplifier OP. The non-inverting input terminal of the operational amplifier OP is connected to the control unit 30A, and the output terminal of the operational amplifier OP is connected to the input / output terminal of the multiplexer 32. The inverting input terminal of the operational amplifier OP is connected to a third connection point between each of the multiple electrical stimulation units 10a-10d and the shunt resistor. The third connection point in this embodiment is the same as the third connection point N3 in the first embodiment.

[0049] The multiplexer 32 includes at least one input terminal connected to the output terminal of the operational amplifier OP, and a plurality of output terminals corresponding to the input terminal, and is capable of outputting the input signal to the input terminal to any of the plurality of output terminals. Each of the plurality of output terminals of the multiplexer 32 is connected to one of the control terminals of the second switching elements Q2a-Q2d and the fourth switching elements Q4a-Q4d of each of the plurality of electrical stimulation units 10a-10d. In Figure 7, for simplification, only the connections to the second switching elements Q2a, Q2b and the fourth switching elements Q4a, Q4b are shown for the plurality of output terminals of the multiplexer 32.

[0050] Figure 8 is a truth table that defines the relationship between the logic of the SEL_A signal line and the SEL_B signal line and the switching element to be turned on. When the logic of the SEL_A signal line and the SEL_B signal line are "L" and "L", the multiplexer 32 connects the EMS_H signal line to the first drive circuit Dr1a of the first system, and connects the EMS_L signal line to the fourth switching element Q4a of the first system, thereby making the first switching element Q1a and the fourth switching element Q4a of the first electrical stimulation unit 10a conductive.

[0051] The multiplexer 32 connects the EMS_H signal line to the first system's third drive circuit Dr3a and the EMS_L signal line to the first system's second switching element Q2a when the logic of the SEL_A signal line and SEL_B signal line are "H" and "L", respectively, thereby making the third switching element Q3a and the second switching element Q2a of the first system's electrical stimulation unit 10a conductive.

[0052] The multiplexer 32 connects the EMS_H signal line to the second system's first drive circuit Dr1b and the EMS_L signal line to the second system's fourth switching element Q4b when the logic of the SEL_A signal line and SEL_B signal line are "L" and "H", respectively, thereby making the first switching element Q1b and the fourth switching element Q4b of the second system's electrical stimulation unit 10b conductive.

[0053] If the logic of the SEL_A signal line and the SEL_B signal line is "H" and "H", the multiplexer 32 connects the EMS_H signal line to the second system's third drive circuit Dr3b, and connects the EMS_L signal line to the second system's second switching element Q2b, thereby making the third switching element Q3b and the second switching element Q2b of the second system's electrical stimulation unit 10b conductive.

[0054] In the case of an electrical stimulation device 3 equipped with four electrical stimulation units 10 using the circuit configuration example shown in Figure 6, the H-bridge circuit has eight conduction patterns, requiring 3 bits of logic and thus three SEL signal lines.

[0055] With the above configuration, the operational amplifier OP performs negative feedback operation, and the potential of the inverting input terminal is equal to the reference voltage V applied to the non-inverting input terminal. REF Each switching element is controlled to be equal to the given value. In this embodiment, the integrated control unit 80 and the shunt resistor constitute a constant current circuit. Thus, in this embodiment, multiple electrical stimulation units 10a-10d can be controlled using a single operational amplifier OP. Furthermore, the control unit 30A in this embodiment can control the intensity of the pulse current flowing to the load of muscles, etc., in various parts of the human body Hd to change over multiple cycles by changing the reference voltage used for each of the multiple electrical stimulation units 10a-10d in each cycle. This makes it possible to apply diverse stimuli to muscles in multiple parts of the human body Hd. In addition, from the viewpoint of changing the intensity of the pulse current, it is preferable to use an analog multiplexer as the multiplexer 32.

[0056] The control unit 30A may control the switching elements of each of the multiple electrical stimulation units 10a-10d so that phase-shifted pulse voltages are applied between the first electrode sections P1a-P1d and the second electrode sections P2a-P2d of each of the multiple electrical stimulation units 10a-10d. This ensures that the intensity of each output pulse is maintained even when sufficient power is not obtained from the DC power supply unit 20. Furthermore, it is possible to stimulate muscles in multiple parts of the human body Hd at different timings via each of the multiple electrical stimulation units 10a-10d.

[0057] As described above, each embodiment of the electrical stimulation device comprises a DC power supply unit 20 and an electrical stimulation unit 10 powered by the DC power supply unit 20. The electrical stimulation unit 10 includes a first switching element Q1 and a second switching element Q2 connected in series between the high-side reference line and the low-side reference line of the DC power supply unit 20, a first electrode unit P1 connected to a first connection point N1 between the first switching element Q1 and the second switching element Q2 to be in contact with a part of the human body Hd, a third switching element Q3 and a fourth switching element Q4 connected in series between the high-side reference line and the low-side reference line, and a second electrode unit P2 connected to a second connection point N2 between the third switching element Q3 and the fourth switching element Q4 to be in contact with another part of the human body Hd. Each embodiment of the electrical stimulation device further comprises a current control unit capable of controlling the current flowing from the electrical stimulation unit 10 to the low-side reference line.

[0058] As a result, the electrical stimulation device of each embodiment can reduce the influence of the load on the human body Hd and control the current flowing between the pair of first electrode section P1 and second electrode section P2. Therefore, the electrical stimulation device of each embodiment can apply a variety of electrical stimuli to the human body Hd.

[0059] In the electrical stimulation device of each embodiment, the current control unit is connected to a shunt resistor R between the electrical stimulation unit 10 and the low-side reference line. SH And the operational amplifier OP and the reference voltage V applied to the non-inverting input terminal of the operational amplifier OP. REF It may also include a control unit 30 that controls the operation amplifier OP. The inverting input terminal of the operational amplifier OP is connected to the electrical stimulation unit 10 and the shunt resistor R SH It may be connected between them. The output terminal of the operational amplifier OP may be connected to at least one of the control terminals of the second switching element Q2 and the fourth switching element Q4. As a result, in the electrical stimulation device of each embodiment, even if an existing boost circuit is used, the influence of the load on the human body Hd on the current flowing between the pair of first electrode section P1 and second electrode section P2 can be reduced.

[0060] In the electrical stimulation device of each embodiment, the control unit 30 may control the first switching element Q1 and the fourth switching element Q4 to the ON state and the second switching element Q2 and the third switching element Q3 to the OFF state to apply a positive pulse voltage between the first electrode section P1 and the second electrode section P2, or it may control the first switching element Q1 and the fourth switching element Q4 to the OFF state and the second switching element Q2 and the third switching element Q3 to the ON state to apply a negative pulse voltage between the first electrode section P1 and the second electrode section P2, and in one cycle, at least one of the positive pulse voltage and the negative pulse voltage may be applied at least once each, and an interval period may be inserted after the application of the at least one pulse voltage, and the reference voltage V REF By changing the pulse current I at each cycle, EMS The intensity of the stimulus may be controllable to change over multiple cycles. This allows for diverse stimuli to be applied to the muscles of the human body (Hd).

[0061] In the electrical stimulation device of each embodiment, the control unit 30 controls the pulse current I EMS The intensity of the pulse may be controlled to change sinusoidally over multiple cycles. This allows for a relaxing effect on the muscles of the human body, particularly deep muscles such as the psoas muscle.

[0062] Each embodiment of the electrical stimulation device may include a plurality of electrical stimulation units 10, and may further include a multiplexer 32 that includes at least one input terminal and a plurality of output terminals corresponding to the input terminal, and is capable of outputting an input signal to the input terminal to any of the plurality of output terminals, the output terminal of the operational amplifier OP being connected to the input terminal of the multiplexer 32, and each of the plurality of output terminals of the multiplexer 32 being connected to a control terminal of either the second switching element Q2 or the fourth switching element Q4 of the plurality of electrical stimulation units 10. This makes it possible to control multiple electrical stimulation units 10 using a single operational amplifier OP.

[0063] In each embodiment of the electrical stimulation device, the control unit 30 may control the switching elements of each of the multiple electrical stimulation units 10 so that phase-shifted pulse voltages are applied between the first electrode unit P1 and the second electrode unit P2 of each of the multiple electrical stimulation units 10. This ensures that the intensity of each output pulse is maintained even when sufficient power cannot be obtained from the DC power supply unit 20. Furthermore, it is possible to stimulate muscles in multiple parts of the human body Hd at different timings via each of the multiple electrical stimulation units 10.

[0064] The present invention has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their respective components and processing processes, and that such modifications are also within the scope of this disclosure.

[0065] For example, the multiplexer 32 in the second embodiment is also applicable to the first embodiment. As a result, the electrical stimulation device 1 according to the first embodiment can use one operational amplifier OP instead of two operational amplifiers OP1 and OP2. [Explanation of Symbols]

[0066] 1,3 Electrical stimulator, I EMS Pulse current, N1 First connection point, N2 Second connection point, N3 Third connection point, OP, OP1, OP2 Operational amplifier, P1 First electrode section, P2 Second electrode section, Q1-Q4 Switching elements, R SH Shunt resistor, V REF Reference voltage, 10 electrical stimulation unit, 20 DC power supply unit, 30, 30A control unit, 32 multiplexer, 50 constant current circuit.

Claims

1. DC power supply unit, An electrical stimulation unit to which power is supplied from the DC power supply unit, Equipped with, The aforementioned electrical stimulation unit is A first switching element and a second switching element are connected in series between the high-side reference line and the low-side reference line of the DC power supply unit. A first electrode portion, which is to be in contact with a part of the human body, is connected to a first connection point between the first switching element and the second switching element, A third switching element and a fourth switching element are connected in series between the high-side reference line and the low-side reference line, It includes a second electrode portion connected to a second connection point between the third switching element and the fourth switching element, which is to be in contact with other parts of the human body, The system further includes a current control unit capable of controlling the current flowing from the electrical stimulation unit to the low-side reference line. Electrical stimulation device.

2. The current control unit, A shunt resistor connected between the electrical stimulation unit and the low-side reference line, Operational amplifier and A control unit that controls the reference voltage applied to the non-inverting input terminal of the operational amplifier, Includes, The inverting input terminal of the operational amplifier is connected between the electrical stimulation unit and the shunt resistor. The output terminal of the operational amplifier is connected to at least one of the control terminals of the second switching element and the fourth switching element. The electrical stimulation device according to claim 1.

3. The control unit, The first switching element and the fourth switching element are controlled to be in the ON state, and the second switching element and the third switching element are controlled to be in the OFF state, thereby enabling the application of a positive pulse voltage between the first electrode portion and the second electrode portion. The first switching element and the fourth switching element are controlled to be in the off state, and the second switching element and the third switching element are controlled to be in the on state, thereby enabling the application of a negative pulse voltage between the first electrode portion and the second electrode portion. In one cycle, at least one of the positive pulse voltage and the negative pulse voltage is applied at least once each, and an interval period is inserted after the application of the at least one pulse voltage. By changing the aforementioned reference voltage with each period, the intensity of the pulse current can be controlled to change over multiple periods. The electrical stimulation device according to claim 2.

4. The control unit is capable of controlling the intensity of the pulse current to change sinusoidally over multiple periods. The electrical stimulation device according to claim 3.

5. The electrical stimulation unit comprises multiple units, The system further includes a multiplexer that includes at least one input terminal and a plurality of output terminals corresponding to the input terminal, and is capable of outputting an input signal to the input terminal to any of the plurality of output terminals. The output terminal of the operational amplifier is connected to the input terminal of the multiplexer, and each of the multiple output terminals of the multiplexer is connected to the control terminal of either the second switching element or the fourth switching element of the multiple electrical stimulation units. The electrical stimulation device according to claim 3 or 4.

6. The control unit controls each switching element of each of the multiple electrical stimulation units so that a phase-shifted pulse voltage is applied between the first electrode and the second electrode of each of the multiple electrical stimulation units. The electrical stimulation device according to claim 5.

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